


From an Outsider's Perspective

by MaggicSorceress



Series: Maggic's Undertale Human AU [5]
Category: Undertale (Video Game)
Genre: Alternate Universe - Human, Alternate Universe - Modern Setting, Cross has no idea whats going on, Fluff and Angst, Fluff and Humor, Gen, M/M, are accurately portrayed siblings, in which Dream and Nightmare
Language: English
Status: Completed
Published: 2020-02-01
Updated: 2020-02-01
Packaged: 2021-02-25 16:54:54
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,861
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22499398
Author URL: https://archiveofourown.org/users/MaggicSorceress/pseuds/MaggicSorceress
Summary: Cross thinks Dream and Nightmare are strange.After all, shouldn't brother's be a little nicer to each other?
Relationships: Dream/Cross, Nightmare & Dream, Sans/Sans (Undertale)
Series: Maggic's Undertale Human AU [5]
Series URL: https://archiveofourown.org/series/1623928
Comments: 8
Kudos: 135





	From an Outsider's Perspective

Nightmare and Dream’s relationship was…strange, to say the least. There were times when they could be so kind to each other, and times when they couldn’t be in the same room without physically maiming each other. But weirder were the times when they were just…odd to each other.

Cross was over at their house one day to visit Dream. The two of them were lounging peacefully in Dream’s bed, some movie playing softly in the background as they cuddled, sharing occasional kisses, when the door to Dream’s room opened without warning and the older twin looked in. Dream, flushing slightly, glowered at him.

“Do you mind?” He asked, gesturing to his and Cross’s current position.

“No.” Nightmare deadpanned. “Do you want chicken nuggets?”

Dream raised an eyebrow and shrugged. “Sure.” Then, without another word, Nightmare shut the door and left. Cross blinked at the closed door, confused.

~

Another occasion that happened when he was over was more of the sort of thing he was used to with them.

“Dream for the last time, stop stealing my shit!”

“You said I could!”

“When?”

“Like four days ago!”

“That’s my favourite shirt why the hell would I let you borrow it?”

“I don’t know but you did!”

Cross sighed and continued to scroll through his Instagram, sitting patiently on their living room couch while he waited for things to calm down a bit.

“Don’t act all high and mighty.” Dream was saying. “You steal my stuff all the time!”

“Since when?!”

“Since always!”

“Name one thing I’ve stolen from you.”

“My tablet.”

“Yeah bu-“

“My chocolate bunny on Easter.”

“We were five!”

“My copy of Lord of the Flies.”

“Mine got stolen!”

“Should I keep going?” Dream sounded smug, dropping down onto the couch next to Cross. “ _Relax_. I didn’t rip it or anything.” Nightmare let out a quite fed up sounding sigh and left the room. Cross raised an eyebrow at his boyfriend.

“You guys are weird.” He told Dream, slipping his phone into his pocket as Dream cuddled up into his side.

“What? You mean you don’t take your brother’s stuff?” Dream asked.

Cross shook his head. “Nah, his clothes don’t fit me. And even if they did, he wouldn’t bitch about it like Nightmare does.” That got Dream to laugh and they settled into the now peaceful atmosphere.

~

As innocent as people liked to believe Dream was, Cross knew the other had a penchant for trouble making. _Especially_ if it had to do with his brother. Cross couldn’t blame him; it was _way_ too fun to piss Nightmare off. Which is how he got into his current predicament. He had spent the night at Dream's house, and was sitting quietly at his kitchen table while Dream munched on what had to be his fourth or fifth bowl of cereal, the empty box sitting next to him with a jug of milk, when a very disgruntled looking Nightmare emerged from the kitchen with a bowl.

“Morning.” Cross greeted, trying not to sound suspicious. He got a non-committed grunt in response as Nightmare reached for the cereal box. When he had tipped it to pour the cereal into his bowl and nothing came out, he looked puzzled for a moment.

“Who ate all the-“ Nightmare started, stopping as his gaze drifted to his brother peacefully snacking away. Cross could see the gears turn and click before Nightmare smacked Dream in the face with the box so hard the milk in the other’s bowl spilt. “Fat-ass!”

Cross snorted, trying desperately to hold in his laughs as Nightmare rose from his seat and stormed back into the kitchen. When Dream looked over at him, face red and covered in milk, the two of them burst into raucous laughter, Cross’s head hitting the table with a dull thud as tears of mirth filled his eyes.

~

The first time he had come to Dream’s house had been…awkward. Firstly, because he had no idea his date had a twin brother, and secondly, that twin brother had stared at him like he had just murdered several small children in cold blood. He had come to pick up Dream for a dinner date when the door was opened by his brother instead. Despite the dark clothes the other wore and the equally dark hair, it was easy to see their resemblance. Both their eyes were blue, although Dream’s seemed lighter and less green by comparison, and they had the same bone structure: soft cheekbones, strong jaw, and the same curve to their nose. Dream’s twin however had no sweet smile to offer him when they met.

“Dream!” He called over his shoulder, gaze never leaving Cross’s own. “Your date is here.” Under the other’s gaze, he broke into a bit of a cold sweat. He wasn’t sure how someone’s eyes could pick someone apart like that, but he was definitely being picked apart.

“You’re Dream’s brother?” Cross asked, though he already knew the answer. “I’m Cross.”

“Yeah, did it take you a while to figure that out?” Dream’s brother snarked in response to his question. “And I know who you are.” Cross let the hand that he had extended drop and fought to keep the smile on his face.

“O-oh…right…” Cross mumbled. Dream’s brother, he still didn’t know his name, folded his arms and glared at him from the doorway.

“Look, I’m not gonna beat around the bush with stupid pleasantries okay?” The other spoke, brows furrowing more. “If this is all some joke or dare then you can leave right now. I won’t have my brother getting attached to some scumbag who’s only doing this for the laughs.” A sudden understanding sparked in Cross and he met Dream’s brother’s gaze purposefully.

“I’m not doing this for shits-and-giggles if that’s what you’re trying to ask me.” Cross said, standing a little straighter. “And if all goes well, I’d like to think I won’t be a ‘scumbag’ that your brother gets attached to.” The dark-haired man raised a well plucked eyebrow at him.

“Night, I swear if you’re trying to scare off my date _again_ …” Dream’s voice chimed from the staircase behind his brother. The other twin shrugged, moving out of the doorway to let Dream pass.

“I’m not. This one’s got balls.”

That was the first, and one of the only, compliments he ever got from the other twin. When Cross and Dream settled themselves into Cross’s car, Dream turned to him, looking a bit embarrassed.

“Sorry about Nightmare. He means well but…he can be kind of harsh sometimes.” Dream said.

Cross shook his head, trying not to laugh. “ _Nightmare_ , huh? That’s fitting.”

~

It wasn’t always that way though. There were occasions, rare ones, where Cross got to see a side of Dream that scared even _him._ A side that could seemingly only be brought out when his brother was hurt in any way. The first time he witnessed it, and it wasn’t the last for sure, he and Dream were out getting coffee together in the early afternoon.

It was a beautiful day outside, being spring-time and all, and Cross was enjoying not only the taste of his hot chocolate, but the feeling of Dream’s hand intertwined with his under the table, when Dream’s phone rang. Keeping their hands knitted together, Dream pulled out his phone. He stared at the screen, puzzled, before he picked it up.

“Night?” He said into his phone. There were a few moments where Cross couldn’t hear anything, but he watched Dream’s face slowly contort from curiosity to a painful concern. Cross felt a spike of worry for a minute as the two continued their conversation, Cross only really hearing half of it. Dream’s voice was serious, but there was something patient and soft under it all. “Where are you?” Dream asked, brows furrowing more into a look of anger and Cross almost shuddered at the unfamiliar look on his boyfriend’s face. Then, Dream was standing and sliding his phone back into his pocket.

“Sorry Cross.” Dream said, sounding genuinely guilty, but it was hard to take it seriously when Dream’s face looked like he was about to murder someone. “I’ve gotta go. I’ll text you later, yeah?” He spared Cross a quick kiss on the cheek, not waiting for the other to answer before he was speed walking out of the doors of the coffee shop.

Cross didn’t ask him about it later, it didn’t seem like something he should ask about, but when he saw Nightmare a few days after that incident covered in large purple bruises, he made a mental promise to himself that if Dream got a call from Nightmare again, he’d drive Dream to the other himself.

~

Now, even though everything that he had previously said about Dream was true, there was nothing saying that _Nightmare_ didn’t enjoy instigating his twin. Currently, they reminded Cross of five-year-old’s, chasing each other around the house, angry but laughing all the same.

“Nightmare, I swear!” Dream said, laughter in his voice and grin wide across his face as he faced off against his brother over the kitchen island. Nightmare was smiling himself, which Cross had never really seen before, and it only served to make the two look even more similar.

“What?” Nightmare teased. “I’m not doing anything!”

“You have a spray bottle behind your back!” Dream said.

Nightmare, looking like a sly cat, shifted on his feet. “No, I don’t~.”

“Yes, you do!” Dream said, then yelped and ducked down as a cold spray of water hit him in the chest. He scrambled away then, giggles bubbling from his lips as his brother gave chase. Cross watched them chase each other around for a bit, a small smile tugging at his lips, before he went back to scrolling through his phone. Not even seconds after he did that, there was a grunt and the hard sound of something crashing to the carpeted floor. Cross, worried now, raised his head to see what the two of them had broken, only to see them wrestling violently for the spray bottle on the floor. They were still laughing though, few and far in between as they struggled, faces red from exertion. Cross smiled fondly, almost laughing out loud when Nightmare managed to get the upper hand and spray Dream in the face. It was strange to hear the other twin laugh, especially since Cross figured their laughs would sound the same. They didn’t. Dream’s laugh was high and bubbly, sometimes growing loud and boisterous, while Nightmare’s was light and airy, interrupted occasionally by small hiccups of air. If he wasn’t dating the other, or had no value for his life, he would have told Nightmare his laugh was cute.

“Boys.” Cross half scolded. “No roughhousing.”

“Okay, _mom_.” The two of them chorused before falling away into peels of laughter, spray bottle forgotten as they sagged against each other, shoulders shaking.

So, Dream and Nightmare were an enigma that Cross wasn’t sure he’d ever be able to understand. But, underneath all the arguments and fights, he knew first-hand how much they loved each other.

And it was a lot.

**Author's Note:**

> Ah ha, I love these two and I couldn't resist writing something for them  
> Have some quality accurate sibling content my dudes.  
> Also, whoever gets the vine I was referencing at a certain part will get a cookie and I will love you forever.  
> Thanks for reading! Hope you guys liked it!  
> -Maggic


End file.
